Abstract
An inductor inlay, a component carrier, and methods for manufacturing the inductor inlay and the component carrier. The inductor inlay has a magnetic layer stack of interconnected magnetic layers and an electrically conductive structure embedded in the magnetic stack. The electrically conductive structure is configured as an inductor element with a coil-like shape. A component carrier includes a stack with at least one electrically conductive layer structure and at least one electrically insulating layer structure and the inductor inlay with the magnetic layer stack with interconnected magnetic layers and the electrically conductive structure embedded in the magnetic layer stack. Methods for manufacturing the inductor inlay and component carrier are further described.
Claims
1. An inductor inlay, comprising: a magnetic layer stack, comprising a plurality of interconnected magnetic layers; and an electrically conductive structure embedded in the magnetic layer stack, wherein the electrically conductive structure is configured as an inductor element that comprises a coil-like shape.
2. The inductor inlay according to claim 1, wherein the magnetic layer stack comprises exactly two magnetic layers or exactly three magnetic layers.
3. The inductor inlay according to claim 1, wherein the inductor element is embedded horizontally in the magnetic layer stack, or wherein the inductor element is embedded vertically in the magnetic layer stack.
4. The inductor inlay according to claim 1, wherein at least one of the magnetic layers is partially or entirely dielectric; and/or wherein at least one of the magnetic layers comprises a magnetic matrix; and/or wherein the magnetic matrix comprises a dielectric material, in which magnetic particles are embedded, in particular wherein the metallic particles comprise at least one of the group consisting of ferrite, a 3d material, and a 4f material; and/or wherein the magnetic matrix continuously fills a volume around the inductor element; and/or wherein the magnetic matrix comprises a rigid solid and/or a paste; and/or wherein the magnetic matrix is electrically insulating; and/or wherein the relative magnetic permeability .Math..sub.r of the magnetic matrix is in a range from 1.1 to 500, in particular 2 to 150, more in particular 4 to 80; and/or wherein the magnetic matrix comprises at least one material of the group consisting of a ferromagnetic material, a ferrimagnetic material, a permanent magnetic material, a soft magnetic material, a ferrite, a metal oxide, a dielectric matrix, in particular a prepreg, with magnetic particles therein, and an alloy, in particular an iron alloy or alloyed silicon.
5. The inductor inlay according to claim 1, wherein the inductor element is meander-shaped and/or spiral-shaped.
6. The inductor inlay according to claim 1, wherein the inductor element comprises at least two terminal sections exposed with respect to the magnetic layers, in particular with respect to the magnetic layer stack.
7. The inductor inlay according to claim 6, wherein the at least two terminal sections have a larger vertical and/or larger horizontal extension than a central section of the inductor element that is located between said terminal sections.
8. The inductor inlay according to claim 1, wherein the inductor inlay further comprises: at least one electrically conductive via, being a blind via or a through-hole via, that extends at least partially through the magnetic layer stack, and that connects the inductor element to an exterior surface of the inductor inlay, wherein the at least one electrically conductive via is filled at least partially with electrically conductive material, or wherein the at least one electrically conductive via is a hollow lining which is filled at least partially with an electrically insulating material, in particular a resin.
9. A method of manufacturing an inductor inlay, the method comprising: stacking a plurality of magnetic layers to provide a magnetic layer stack, thereby: interconnecting the plurality of magnetic layers; and embedding an electrically conductive structure in the magnetic layer stack, wherein the electrically conductive structure is configured as an inductor element that comprises a coil-like shape.
10. The method according to claim 9, further comprising: forming a dielectric layer, in particular a photo-imageable layer; patterning the dielectric layer to form a patterned dielectric layer; and arranging, in particular plating, a metal in the patterned dielectric layer, thereby forming the inductor element.
11. The method according to claim 10, further comprising: forming a further dielectric layer on the patterned dielectric layer, thereby embedding the inductor element; patterning the further dielectric layer to expose a part of the embedded inductor element; and arranging, in particular plating, a further metal on the exposed part of the inductor element surface, thereby forming terminal sections for the inductor element.
12. The method according to claim 10, further comprising: arranging, in particular laminating, a first magnetic layer onto the inductor element surface, in particular removing the dielectric layer before arranging the first magnetic layer, and/or arranging, in particular laminating, a second magnetic layer onto a back-side surface of the inductor element, wherein the back-side surface is opposed to the inductor element surface.
13. The method according to claim 9, further comprising: providing a temporary carrier with a surface layer, in particular metal layer, arranging the dielectric layer on the surface layer, and wherein patterning the dielectric layer comprises: exposing the surface layer below the patterned dielectric layer; and/or further comprising: removing the temporary carrier with the surface layer before arranging the second magnetic layer on the back-side surface of the inductor element; and/or removing the temporary carrier with the surface layer after arranging the first magnetic layer on the inductor element surface; in particular wherein the removing comprises or consists of at least one of the group which consists of grinding, releasing by UV treatment or laser treatment, etching, in particular dry etching.
14. A component carrier, wherein the component carrier comprises: a stack comprising at least one electrically conductive layer structure and at least one electrically insulating layer structure; and an inductor inlay, wherein the inductor inlay is embedded in the stack, wherein the inductor inlay includes: a magnetic layer stack, comprising a plurality of interconnected magnetic layers; and an electrically conductive structure embedded in the magnetic layer stack, wherein the electrically conductive structure is configured as an inductor element that comprises a coil-like shape.
15. The component carrier according to claim 14, wherein the component carrier is configured as an integrated circuit, IC, substrate, wherein an IC substrate resembles an IC-sized high density PCB; and/or wherein at least one electrically conductive structure of the stack is electrically connected to the inductor element of the inductor inlay, in particular via the terminal sections; and/or wherein the inductor inlay is embedded in the stack, so that the directions of main extension of the inductor inlay are essentially parallel or essentially perpendicular to the directions of main extension of the component carrier.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0107] FIG. 1 shows a side view of an inductor inlay according to an exemplary embodiment of the disclosure.
[0108] FIG. 2 shows a side view of a component carrier with the inductor inlay according to an exemplary embodiment of the disclosure.
[0109] FIG. 3A and FIG. 3B show a top view of the inductor inlay according to an exemplary embodiment of the disclosure.
[0110] FIG. 4 shows a side view of a component carrier with the inductor inlay according to another exemplary embodiment of the disclosure.
[0111] FIG. 5A, FIG. 5B, FIG. 5C, FIG. 5D, FIG. 5E, FIG. 5F, FIG. 5G, FIG. 5H, FIG. 5I, FIG. 5J, and FIG. 5K illustrate a manufacturing method to provide the inductor inlay according to an exemplary embodiment of the disclosure.
[0112] FIG. 6A, FIG. 6B, and FIG. 6C show a further manufacturing method to provide the inductor inlay according to another exemplary embodiment of the disclosure.
[0113] FIG. 7A, FIG. 7B, FIG. 7C, FIG. 7D, and FIG. 7E show different design of the inductor element.
[0114] FIG. 8 shows a simulation of the inductance value with respect to the designs of FIG. 7A to FIG. 7E.
[0115] FIG. 9A and FIG. 9B show different thicknesses of the inductor element in relation to the magnetic layer stack.
[0116] FIG. 10 shows a simulation of the inductance value with respect to the designs of FIG. 9A and FIG. 9B.
[0117] FIG. 11A, FIG. 11B, and FIG. 11C show different line/space ratios of the inductor element and the magnetic matrix.
[0118] FIG. 12 shows a simulation of the inductance value with respect to the designs of FIG. 11A to FIG. 11C.
[0119] FIG. 13A, FIG. 13B, and FIG. 13C show an inductor inlay according to an exemplary embodiment of the disclosure, respectively.
[0120] FIG. 14 shows a side view of an inductor inlay according to a further exemplary embodiment of the disclosure.
[0121] FIG. 15 shows a side view of an inductor inlay according to a further exemplary embodiment of the disclosure.
DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS
[0122] The illustrations in the drawings are schematically presented. In different drawings, similar or identical elements are provided with the same reference signs.
[0123] Before, referring to the drawings, exemplary embodiments will be described in further detail, some basic considerations will be summarized based on which exemplary embodiments of the disclosure have been developed.
[0124] According to an exemplary embodiment, the disclosure uses inductor inlays which are embedded in the inner layers of the substrate core of a component carrier, e.g., by ECP® technology. On the one hand side, these inlays allow the usage of materials with higher magnetic permeability, on the other hand the design can be optimized and tailored to a dedicated application. As a consequence, the inlays can achieve much higher inductance which is required for the next generations of microprocessors and substrates. Further, this disclosure describes processes to manufacture inductor inlays from magnetic sheets with embedded copper structures.
[0125] FIG. 1 shows a side view of an inductor inlay 150 according to an exemplary embodiment of the disclosure. The inductor inlay 150 comprises a magnetic layer stack 160 with a plurality of interconnected magnetic layers. Between a first magnetic layer 161 and a second magnetic layer 162, there is arranged an electrically conductive structure 120 embedded in the magnetic layer stack 160. The electrically conductive structure 120 is configured as an inductor element 120 that comprises a coil-like shape. In between the coil-like shape, there is arranged magnetic material (which continuously fills a space between conductor track and magnetic matrix and) which can be considered as a third magnetic layer 163 of the magnetic stack 160.
[0126] The inductor inlay 150 is shaped as a plate (i.e., planar) and can comprises an ultra-thin thickness (e.g., 100 .Math.m thick and 1000 .Math.m in length). The electrically conductive structure 120 is arranged in the center of the inductor inlay 150, both in the vertical direction (along the z-axis) and in the horizontal direction (along the x- and y-axes). The electrically conductive structure 120 comprises windings (see also FIG. 3). The inductor inlay 150 is configured so that, depending on the thickness and the shape of the electrically conductive structure 120, a specific inductance value is provided for the inductor inlay 150. This inductance value can be adjusted based on e.g., the thickness and the shape of the electrically conductive structure 120. Further, the magnetic permeability of the magnetic matrix 155 can be chosen accordingly.
[0127] The inductor element 120 comprises at least two terminal sections 165 exposed with respect to the magnetic layers 161, 162 and/or the magnetic layer stack 160. The terminal sections 165 have a larger vertical (along the z-direction) extension than a central section 166 of the inductor element 120 that is located between said terminal sections 165. In this example, the terminal sections 165 are configured as electrically conductive blind vias, that extend at least partially through the magnetic layer stack 160 (here through the second magnetic layer 162) and connect the inductor element 120 to an exterior (main) surface of the inductor inlay 150. Both terminal sections 165 are orientated to the same upper main surface of the inductor inlay 150, where they can be electrically connected to pads and/or vias and/or conductor tracks. This design reflects a manufacturing process (see FIG. 5 below), wherein a two-step build-up (using e.g., photolithography) on a temporary carrier is applied.
[0128] FIG. 2 shows a side view of a component carrier 100 with the inductor inlay 150 according to an exemplary embodiment of the disclosure.
[0129] The component carrier 100 comprises a layer stack 110 with electrically conductive layer structures 104 and electrically insulating layer structures 102. The center of the component carrier 100 constitutes an insulating core layer structure 103 (e.g., fully cured resin such as FR4). Electrically conductive through connections in the form of vias extend through the core structure 103 to thereby electrically connect a first (top) main surface with an opposite second (bottom) main surface of the component carrier 100.
[0130] The above-described inductor inlay 150 is embedded within the insulating core layer structure 103 and encapsulated with electrically insulating layer stack material 102. In the example shown, the inductor inlay 150 is embedded so that main surfaces of the insulating core structure 103 and the inductor inlay 150 are flush (both comprise a respective thickness of 100 .Math.m).
[0131] The two terminal sections 165 are electrically connected through pads to electrically conductive structures (blind vias) 104 of the component carrier 100. Thereby, the inductor inlay 150 is fully integrated and connected to the component carrier 100.
[0132] FIG. 3A shows a top view of the inductor inlay 150 according to an exemplary embodiment of the disclosure. It can be seen that the inductor element 120 is formed by an electrically conductive structure 120 (e.g., copper) winding that is formed in the magnetic material 155 in a rectangular coil-like manner. In the example shown, the element 120 comprises seven windings. A starting point and an end point of the windings 120 are respectively electrically connected to a terminal (in particular by the via 165). When an electric current is provided to the inductive element 120, an inductance is provided which is in turn enhanced by the magnetic permeability of the magnetic matrix 155. Since the stack 160 comprises a planar shape, the electrically conductive structure 120 is oriented horizontally with respect to the component carrier 100. By providing the magnetic matrix 155, a large amount of magnetic material can be applied and, as a consequence, a high inductance value can be obtained.
[0133] FIG. 3B shows a side view of the inductor inlay 150 of FIG. 3A, wherein the magnetic flux in indicated by arrows.
[0134] FIG. 4 shows a component carrier 100 according to another exemplary embodiment of the disclosure. While in FIG. 2 the inductor inlay 150 is arranged horizontally in the component carrier 100 (i.e., the directions of main extension (along the indicated x and y axes) of the inductor inlay 150 are oriented in parallel with the directions of main extension of the component carrier 100), there are a plurality of inductor inlays 150 oriented vertically in the component carrier 100 (i.e., the direction of main extension (along the indicated x axis) of the inductor inlay 150 is oriented perpendicular with the direction of main extension (x) of the component carrier 100). The terminal sections 165 of the inductor inlay 150 are electrically connected to respective blind vias 104 of the component carrier 100 along the z-direction. In the example shown, the inductor inlays 150 are embedded in the insulating core layer structure 103 of the component carrier 100. The component carrier 100 further comprises through-hole vias that are oriented in parallel with the embedded inductor inlays 150. The inductor inlays 150 can comprise a respective length of 1000 .Math.m (same as the insulating core structure 103), so that exposed surfaces of the inductor inlay 150 may be flush with the upper/lower main surface of the insulating core layer structure 103. In another example, the inductor inlays can be embedded in one or more electrically insulating layer structures that are not necessarily core structures.
[0135] FIG. 5A, FIG. 5B, FIG. 5C, FIG. 5D, FIG. 5E, FIG. 5F, FIG. 5G, FIG. 5H, FIG. 5I, FIG. 5J, and FIG. 5K illustrate a manufacturing method to provide the inductor inlay 150 according to an exemplary embodiment of the disclosure.
[0136] In FIGS. 5A and 5B a temporary carrier 170 is provided, wherein the temporary carrier 170 comprises a resin, preferably a grindable resin such as FR1. A copper foil 171 is provided on a copper carrier and laminated to one of the main surfaces of the temporary carrier 170.
[0137] In FIG. 5C the copper carrier is removed, thereby leaving the copper foil 171 attached to said temporary carrier 170 main surface.
[0138] In FIG. 5D a dielectric layer 180 is arranged on the copper foil 171. The dielectric layer 180 comprises in this example a PID (photo-imageable dielectric) material.
[0139] In FIG. 5E the dielectric layer 180 is patterned, whereby dielectric material is removed to partially expose the copper foil 171 in an exposed structured part 172. In this example, photolithography is used to structure (expose and develop) the PID material 180. The exposed structured part 172 comprises a coil-like shape.
[0140] In FIG. 5F the exposed structured part 172 of the dielectric layer 180, where the surface of the copper foil 171 is exposed, is filled (for example plated) with copper, thereby forming the inductor element 120, wherein the electrically conductive structure 120 is configured as the inductor element 120, that comprises a coil-like shape, in a structured and plated dielectric layer 183.
[0141] In FIG. 5G a further dielectric layer 181 (which comprises in this example also a PID (photo-imageable dielectric) material) is arranged on the dielectric layer 180 and the inductor element 120, so that the inductor element 120 is fully encapsulated by dielectric material 180, 181.
[0142] In FIG. 5H the further dielectric layer 181 is patterned, whereby dielectric material is removed to only partially expose the embedded inductor element 120. In this example, photolithography is used to structure (expose and develop) the further PID material 181. The structured part comprises a shape of a blind via and exposes a surface 121 of the inductor element 120.
[0143] In FIG. 5I the structured part of the further dielectric layer 181, where the surface of the embedded inductor element 120 is exposed, is filled (for example plated) with copper, thereby forming terminal sections 165 for the inductor element 120.
[0144] In FIG. 5J the dielectric layer 180 and the further dielectric layer 181 are fully removed (stripped), thereby exposing the inductor element 120 with its vertically enlarged terminal sections 165. The manufacturing process of forming the inductor element 120 with the terminals 165 in a two-step process on a temporary carrier is reflected in the final product in that both terminals are oriented to the same inductor inlay main surface.
[0145] In FIG. 5K a first magnetic layer 161 is arranged (laminated) onto the inductor element surface 121. The inductor element 120 gets fully encapsulated by magnetic material 155, so that a third magnetic layer 163 is formed in between the windings of the coil. The magnetic layer 161, 163 can be provided as a magnetic material sheet (instead of a paste).
[0146] FIG. 6A, FIG. 6B, and FIG. 6C show a further manufacturing method (based on the method describes for FIG. 5) to provide the inductor inlay 150 according to another exemplary embodiment of the disclosure.
[0147] In FIG. 6A the temporary carrier 170, which includes the copper foil 171, of the product of FIG. 5K is removed. Removing can for example be done by grinding the grindable material 170 and also the copper foil 171. The inductor element 150 is now partially exposed at its back-side surface 122 (which is opposed to the surface 121).
[0148] In FIG. 6B a second magnetic layer 162 is arranged (laminated) onto the back-side surface 122 of the inductor element 120, wherein the back-side surface 122 is opposed to the inductor element surface 121. Again, the inductor element 120 is fully encapsulated, but not in the dielectric layers 180, 181, but in magnetic matrix material 155. By interconnecting the first magnetic layer 161 and the second magnetic layer 162 (and the third magnetic layer 163), the magnetic layers 161, 162, 163 are stacked to provide the magnetic layer stack 160.
[0149] In FIG. 6C the inductor inlay 150 with the magnetic layer stack 160, as described for FIG. 1, is now obtained. The upper main surface can be processed, in particular grinded, to expose the conductive terminals 165 of the embedded inductor element 120.
[0150] FIG. 7A, FIG. 7B, FIG. 7C, FIG. 7D, and FIG. 7E show different designs of the inductor element 120.
[0151] In FIG. 7A the inductor element has a square, or rectangular coil-shape.
[0152] In FIG. 7B the inductor element has a circular coil-shape.
[0153] In FIG. 7C the indictor element has a hexagonal (rectangular) coil-shape.
[0154] In FIG. 7D the inductor element has an octagonal (rectangular) coil-shape.
[0155] In FIG. 7E the inductor element has a meander-like coil-shape.
[0156] FIG. 8 shows a simulation of the inductance value with respect to the designs described for FIG. 7. On the x-axis, there is given the permeability (.Math.), while the inductance (in nH) is provided along the y-axis. It can be seen that the squared coil-shape shows an improved inductance compared to the other designs. For example, the square uses more efficiently the area (frequency resistance) than the circle. The square has further a longer conductor track than the hexagon.
[0157] FIG. 9A and FIG. 9B show different thicknesses of the inductor element 120 in relation to the magnetic layer stack 160.
[0158] As illustrated in FIG. 9A, the thickness (height along z) of the inductor element 120 is high, for example 50 .Math.m, while the first and second magnetic layers 161, 162 have a thickness of 25 .Math.m respectively.
[0159] In FIG. 9B the thickness (height along z) of the inductor element 120 is low, for example 18 .Math.m, while the first and second magnetic layers 161, 162 have a thickness of 41 .Math.m respectively.
[0160] FIG. 10 shows a simulation of the inductance value (using a square shape) with respect to the designs of FIG. 9 (and a further design with a 35 .Math.m thick inductor element 120). It can be seen that a higher inductance value can be achieved with thicker magnetic layers 161, 162 (FIG. 9B) in comparison to a thicker inductor element 120. Thus, a high magnetic layer material/inductor element material ratio can be preferable.
[0161] FIG. 11A, FIG. 11B, and FIG. 11C show different line (conductor track)/space (magnetic material) ratios (along the horizontal direction) of the inductor element 120 (using a square, 18 .Math.m height) and the magnetic layer stack 160.
[0162] In the example illustrated in FIG. 11A, the line/space ratio is 50/50 .Math.m (low number of windings, thick conductor track).
[0163] In the example illustrated in FIG. 11B, the line/space ratio is 35/45 .Math.m.
[0164] In the example illustrated in FIG. 11C, the line/space ratio is 20/20 .Math.m (high number of windings, thin inductor trace).
[0165] FIG. 12 shows a simulation of the inductance value with respect to the inductor element (using square, 18 .Math.m thickness) designs of FIG. 11. It can be seen that, the smaller the lines and spaces are (20/20 .Math.m is here preferable), the larger is the inductance value. It should be kept in mind, however, that high inductance values are not strictly the perfect choice, since the Rdc values have to be considered as well and should not be too high. In this context, the term Rdc value may describe how much resistance will be present at direct current, whereby less resistance may be desired in the present case.
[0166] FIG. 13A shows an embodiment of the inlay 150, where the magnetic stack 160 comprises two inductor elements 120a, 120b stacked one above the other in the z-direction. The magnetic stack 160 comprises in this example five magnetic layers, two for embedding the inductor elements 120a, 120b respectively, and three above, below, and in between, respectively. In this example, the inductor element 120a and the further inductor element 120b are perfectly aligned in the z-direction.
[0167] FIG. 13B shows a further embodiment of the inlay 150, where the magnetic stack 160 comprises two inductor elements 120a, 120b stacked one above the other in the z-direction. However, in this example, the inductor element 120a and the further inductor element 120b are not perfectly aligned but shifted with respect to each other.
[0168] FIG. 13C shows an embodiment of an inductor element arrangement that comprises two of the described inductor inlays 150a, 150b stacked on top of each other. By this measure, a very similar architecture as described for FIGS. 13a and 13b can be obtained. While in this embodiment, the respective inductor elements 120a, 120c are aligned in the vertical direction, there can be no alignment in another embodiment.
[0169] FIG. 14 shows the inductor inlay 150 according to a further exemplary embodiment. In this example, the terminal section 165 is arranged at the edge portion of the inductor inlay 150, i.e., is flush with a sidewall of the inductor inlay 150. Further, the terminal section 165 is flush with one main surface (top or bottom) of the inductor inlay 150. This specific embodiment can be manufactured using a subtractive or additive (in particular (m)SAP) process, for example using the method described in FIG. 5. Depending on the manufacture process, the inductor element 120 can be formed with two process steps, so that there can be a demarcation line in the inductor element 120 along the horizontal direction.
[0170] FIG. 15 shows the inductor inlay 150 according to a further exemplary embodiment. This example is very similar to the one shown in FIG. 14, with the difference that the terminal section 165 is additionally exposed at both (opposed) main surfaces of the inductor inlay 150.
[0171] It should be noted that the term “comprising” does not exclude other elements or steps and the article “a” or “an” does not exclude a plurality. Also, elements described in association with different embodiments may be combined.
[0172] Implementation of the disclosure is not limited to the preferred embodiments shown in the figures and described above. Instead, a multiplicity of variants is possible which variants use the solutions shown and the principle according to the disclosure even in the case of fundamentally different embodiments.
TABLE-US-00001 Reference Signs 100 Component carrier 102 Electrically insulating layer structure 103 Core layer structure 104 Electrically conductive layer structure, via of component carrier 110 Layer stack 120 Inductor element, conductive track 120a Inductor element 120b Further inductor element 120c Other inductor element 121 Inductor element surface 122 Inductor element back-side surface 150 Inductor inlay 150a Inductor inlay 150b Further inductor inlay 155 Magnetic material (matrix) 160 Magnetic layer stack 161 First magnetic layer 162 Second magnetic layer 163 Third magnetic layer, embedding part 165 Terminal section 166 Central section 170 Temporary carrier 171 Metal layer 172 Exposed part of metal layer 180 Dielectric layer 181 Further dielectric layer 183 Patterned (and plated) dielectric layer
